new: add string replace method example

Author: ronthetech

python/examples/string-replace-method.py

@@ -0,0 +1,8 @@
+message1 = "Hi, I'm a Python Expert!"
+new_message1 = message1.replace("Python", "Ruby")  
+print(new_message1)
+#  Hi, I'm a Ruby Expert!
+
+message2 = "Where can you find what you need to finish the project that you just started."
+new_message2 = message2.replace("you", "I", 2)  
+print(new_message2)